The present invention relates generally to optical communication systems, and more particularly, to apparatus and method of providing separate control and data channels between arrays of light emitters and detectors for optical communication and alignment.
Greater demands for increased bandwidth are being made on data communication between electrical data processing units or subunits, like printed circuit (PC) boards, for example. Communication rates of tens of gigabits per second are exemplary of such demands. These demands can not be met by traditional metal electrical connections, like those found on mother boards and back plane connections, for example. One solution to meet these demands is to create optical communication channels for unit-to-unit communication using light coupling between an array of light emitters connected electrically to one subunit and an array of light detectors connected electrically to another subunit. In this solution, there is a one-to-one relationship between the light emitters and detectors of the arrays.
A drawback to this solution is that each light emitter of the emitting array must be precisely aligned with a corresponding light detector of the detecting array to form an optical communication channel. This precise alignment is no simple task and generally requires additional equipment and man-hours to achieve. In addition, once the precise alignment is initially achieved, it may have to be repeated from time to time, due to misalignment due to such effects as shock, vibration, temperature changes and the like, for example.
Another drawback is that each optical communication channel generally communicates both data and control information between the units or subunits, thus reducing the available channel bandwidth for data communication. Communicating data and control information over the same channel requires a multiplexing function at one end and a demultiplexing function at the other end. Accordingly, the combination of data and control information over the same channels adds to system design complexity and reduces system performance.
The present invention overcomes the drawbacks of the present optical communication systems and provides apparatus and method which reduces the complexity of system design and improves system performance.